Fuel oil compositions



United States Patent 3,447,915 FUEL OIL COMPOSITIONS Bruce M. Otto, Hammond, Ind., assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Filed Oct. 31, 1966, Ser. No. 590,525

Int. Cl. C101 1/18 US. Cl. 44-62 8 Claims ABSTRACT OF THE DISCLOSURE This invention-relates topetroleurn fuel oil compositions containing pour point depressors.

In storage and use of heavy oils, such as lubricating oils, problems associated with pour point have long been in'existence and have been recognized in the art. The pour point of an oil is defined as the lowest temperature at which the oil will pour or flow when chilled without disturbance 'under specified conditions. Recently, it'has been discovered that pour point problems also exist in the storage and use of petroleum fuel oils, particularly at low temperatures. Pour point problems arise through the formation of solid or semi-solid waxy particles within an oil composition. For example, in the storage of furnace oils or diesel oils during the winter months, temperatures may decrease to a point as low as 15 to -40 F. The decreased temperatures often cause crystallization and solidification of wax in the distillate fuel oil. This problem has been in part remedied by lowering the end point of oils used for blending furnace and diesel oils. It has also been suggested that the distillate fuel oils may be dewaxed such as by urea dewaxing. However, readjustment of end points causes loss of valuable product as blending material for distillate fuel oil stocks. Further, dewaxing operations are expensive.

Another approach in solving the problem has been to attempt to find a pour point depressor which will decrease the pour point of a distillate fuel oil. However, it has been found that the pour point depressors normally used for lubricating oils and other heavy oils are generally ineffective in lowering the pour point of a petroleum fuel oil.

It is an object of the present invention to provide an improved pour point depressor for hydrocarbon fuel oils. Another object of the invention is to provide a hydrocarbon fuel oil composition having a low pour point and fiowable at low temperatures. Still another object of the invention is to provide a method of lowering the pour point of hydrocarbon fuel oils which normally have high pour points and are not pumpable at low temperatures.

In accordance with the present invention, the foregoing objects are attained by incorporating in hydrocarbon fuel oils which normally have high pour points about 0.001%, preferably about 0.010.5%, by volume, of a terpolymer of ethylene, propylene, and an alkyl ester,

3,447,915 Patented June 3, 1969 or mixture of esters, of acrylic acid or methacrylic acid or mixtures thereof, wherein said terpolymer contains about 35-89% ethylene, about 15% propylene, and about 10-60% of the ester. Terpolymers which are especially effective pour depressants contain about 37-70% ethylene, about 2-3% propylene, and about 27-60% of the alkyl ester. The terpolymers herein described are further characterized as having melt indexes (MI) of about 0.5 to 55 grams per minute at C. The melt index is determined by a modified ASTM D-1238 method using a 0.02 inch orifice and a temperature of 80 C.

The alkyl acrylates or methacrylates suitable for use in the present invention are the oil-soluble lower single or mixed alkyl esters of acrylic acid or methacrylic acid containing from 1 to about 12, and preferably from about 2 to about 8, carbon atoms. Illustrative of such lower alkyl esters are the methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, 2-ethyl hexyl, octyl, and dodecyl esters of acrylic acid and of methacrylic acid.

The terpolymers employed in the present invention can be prepared by the polymerization of the ethylene, propylene, and the single or mixed alkyl ester of acrylic acid and/or methacrylic acid in the presence of a free radical catalyst at pressures in the range of about 15,000 to about 50,000 p.s.i. and temperatures in the range of about 250 F. to about 600 F.

The herein described terpolymer pour point depressors are particularly suitable for use in petroleum distillate and residual hydrocrabon fuel oils, such as for example, diesel fuels, jet fuels, heavy industrial residual fuels (e.g. Bunker C), furnace oils, heater oil fractions, kerosene, gas oils, or any other like light oils. The fuel oil may be of virgin or cracked petroleum stock, or mixtures thereof, boiling in the range of from about 200 to about 750 F., and preferably in the range of 350 to 650 F. The fuel oil may contain cracked components, such as, for example, those derived from cycle oils or cycle oil cuts boiling heavier than gasoline, usually in the range of from about 450 to about 750 F. and may be derived by catalytic or thermal cracking. High-sulfur-containing and loW- sulfur-containing oils such as diesel oils and the like may also be used. The fuel oil may, of course, contain other components such as addition agents used to perform particular functions, for example, rust inhibitors, corrosion inhibitors, antioxidants, sludge stabilizing compositions, etc.

The preferred distillate fuel oils have an initial boiling point in the range of from about 350 to about 475 F. and an end point in the range of from about 500 to about 650 F. The distillate fuel oil may advantageously have an A.P.I. gravity of about at least 30 and a flash point (Tag closed cup) not lower than about F. and preferably above about F.

Particularly effective pour point depressors are the terpolymers obtained by the polymerization of a mixture of monomers consisting of ethylene, propylene and Z-ethylhexyl acrylate (ZEHA). Especially effective terpolymers contain about 38-68 wt. percent ethylene, about 2 wt. percent propylene, and about 30-60 wt. percent Z-ethylhexyl acrylate, and have a melt index of about 3-50. The composition, melt index (MI), and effectiveness of such terpolymers is set forth in Table I. The pour point efiectiveness was obtained by adding the indicated terpolymers 3 to various fuel oils and determining the pour points The pour point depressant effect of the herein-described thereof. terpolymer pour point depressors and a commercial fuel TABLE I oil pour point depressor X in distillate fuels having the following specification: Terpolymer Composition, percent Ethylene Propylene 2EHA MI Effectiveness 5 32 2 66 8.25 Low. 35 2 63 35.6 Low. 35 2 63 21.1 Low. 78 2 20 50 Low. 51 2 47 51 LOW- Composition Fuel oil A Fuel oil B 62 2 36 8.8 Moderate. 58 2 40 9.0 D0. Percent Cracked 80 70 66 2 32 5 DO- Percent Straight run 64 2 34 17 Do. Gravity, API 32.6 34.5 58 2 40 8 Do. Distillation, F. 59 2 39 13.1 Moderate high. LB. 374 365 53 2 45 19.6 Do. 418 428 53 2 45 8.5 Do. 501 500 49 2 49 3.2 Do. 584 579 as 2 60 8.2 Do. 632 634 7 3s 2 60 18.3 Do. 0 68 2 30 50 Do. 43 2 55 7.6 High. 43 2 55 5.8 Do. 45 2 53 6.4 Do. 20 46 2 52 7.28 Do. 42 2 56 16.6 Do. 48 2 50 10 Do. 50 2 48 185 11330. 53 2 45 is illustrated in Table III.

TABLE 111 Additive Conc., vol percent Ex. 1 Ex. 10 Ex. 17 Ex. 18 Ex. 29 Ex. 34 Ex. 43 Ex. 50 X Fuel Oil A (Pour point, F.

o 12 12 22 6 10 -14 22 6 4 24 34 46 12 22 44 14 12 *-60 SP *60 SP 18 30 54 *60 SP 28 Fuel oil B (Pour point, F.)

o 10 12 22 4 12 12 22 s 2 13 22 40 10 18 20 30 16 s 26 35 60 16 25 28 46 24 The composition, melt index, and effectiveness of an- Terpolymer Composition, percent Example No. Ethylene Propylene IBA MI Effectiveness 69 2 29 3. 0 Low. 78 2 20 2. 0 Low. 75 2 23 3. 2 Low. 77 2 21 9. 8 Low. 72 2 26 17. 6 Low. 86 2 12 17. 6 Low. 88 2 10 5. 9 Low. 83 2 15 10. 2 Low. 66 2 32 10. 0 Moderate. 65 2 33 1. 8 Do. 81 2 17 51. 5 Do. 80 2 18 42 Do. 78 2 20 34. 5 Do. 66 2 32 19. 6 Do. 63 2 35 18. 5 Do. 70 2 28 30. 2 Do. 73 2 25 27. 9 Do. 44 2 54 6.8 Moderate high. 56 2 42 0. 9 Do. 60 2 38 8. 8 D0. 62 2 36 7. 7 D0. 62 2 36 30. 4 D0. 2 38 32. 5 Do. 50 2 48 4. 6 High. 58 2 40 4. 3 D0. 52 2 46 6. 0 Do. 53 2 45 10. 4 Do. 53 2 45 16. 0 Do. 54 2 44 18. 8 Do. 54 2 44 26. 2 Do.

The addition agents of this invention, may for convenience, be prepared as addition agent concentrates. Accordingly, the tenpolymer is dissolved in a suitable organic solvent therefor in amounts greater than 10% and preferably about 2565%. The solvent in such concentrate may conveniently be present in amounts of about 35- 75%. The organic solvent preferably boils within the range of from about F. to about 700 F. The preferred organic solvents are hydrocarbon solvents, for example, petroleum fractions such as naphtha, kerosene, heater oil, mineral spirits, and the like; aromatic hydrocarbons such as benzene, Xylene and toluene; paralffinic hydrocarbons such as hexane, pentane, etc.; because of their clean burning properties. The sol-vents selected should, of course, be selected with regard to possible beneficial or adverse effects it may have on the ultimate fuel oil composition. Thus, the solvent should preferably burn without leaving a residue and should be non-corrosive with regard to metal, and especially ferrous metals. Other desirable properties are obvious from the intended use of the solvent.

All percentages given herein are percentages by weight unless otherwise indicated.

I claim: 7

1. A hydrocarbon fuel oil composition having improved pour characteristics, comprising a hydrocarbon fuel oil and about 0.001 5% of a terpolymer containing about 3589 wt. percent ethylene, about 1-5 wt. percent propylene, and about 10-60 wt. percent of C alkyl ester of an acid of the group consisting of acrylic acid, methacrylic acid or mixtures thereof, said terpoly- 5 mar having a melt index of about 0.5-55 grams per minute at 80 C.

2. The composition of claim 1 wherein the amount of said terpolymer is about 0.01-0.5%.

3. The composition of claim 2 wherein said acid is acrylic.

4. The composition of claim 3 wherein said alkyl is 2- ethylhexyl.

5. The composition of claim 3 wherein said alkyl is isobutyl.

6. The composition of claim 1 wherein said terpolymer contains about 38-68 wvt. percent ethylene, about 2 wt. pencent propylene, and about 30-60 wt. percent 2-ethy1- hexyl acrylate, and has a melt index of about 3-50.

7. The composition of claim 1 wherein said terpolymer contains about 44-66 wt. percent ethylene, about 2 wt;

percent propylene, and about 32-54 wt. percent isobutyl acrylate, and has a melt index of about 0.9-33.

8. A hydrocarbon fuel oil pour point depressor concentrate comprising essentially a hydrocarbon fuel oil containing from about 25% to about 65% of an active UNITED STATES PATENTS 3,093,623 6/ 1963 llnyckyj 44-62 XR FOREIGN PATENTS 848,777 9/1960 Great Britain. 993,744 6/1965 Great Britain.

DAN I EL E. WYMAN, Primary Examiner. W. J. SI-HNE, Assistant Examiner.

US. Cl. X.R. 4470 

